Borate solution soluble polyvinyl alcohol films

ABSTRACT

Conventional polyvinyl alcohol envelopes will not readily dissolve in wash water which has a significant borate concentration and a pH frequently encountered in wash liquors. Herein, such films are rendered sufficiently soluble in such solutions. In the preferred embodiment this is done by utilizing a polyvinyl alcohol film wherein at least a portion of the polyvinyl alcohol has a number average molecular weight below about 50,000, or a polyvinyl alcohol film containing a polyhydroxy compound having a binding constant with borate of at least about 800M -2 , or utilizing a polyvinyl alcohol film having an acid having an acid dissociation constant of 10 -9  M or larger; or a polyvinyl alcohol film containing mixtures thereof.

This is a division of pending application Ser. No. 577,727 filed Feb. 8,1984, now U.S. Pat. No. 4,526,372 which is a continuation-in-part ofapplication Ser. No. 319,966, filed Nov. 10, 1981, now abandoned.

TECHNICAL FIELD

The invention relates to polyvinyl alcohol films which are soluble inborate containing solutions and more particularly to such films in theform of envelopes containing laundry additives such as detergents andthe like.

BACKGROUND ART

Several film materials are available which are water soluble and whichcan be formed into envelopes in which premeasured amounts of laundryadditives can be sealed. Methyl cellulose, polyethylene oxide andpolyvinyl alcohol are particularly useful film materials of this nature.Methyl cellulose films generally do not have sufficient solubility athigher water temperatures. Polyethylene oxide films tend to absorbmoisture too readily and become tacky.

Polyvinyl alcohol films do not have the problems of methyl cellulose orpolyethylene oxide films. However, when these films are placed insolutions containing borate at levels and pHs frequently encountered inlaundry applications, the rate of solubility of such films is severelyreduced. Yet, borate is often present in clothes washing liquors and thelike, since one of the most widely used bleaching compositions isprincipally sodium perborate, which forms borate ions in solution. Otherborate sources such as borax, are also often used as laundry additives.

DISCLOSURE OF INVENTION

The present invention is directed to overcoming the problem of slowdissolution rates of polyvinyl alcohol films in borate containingsolutions as set forth above.

In accordance with an embodiment of the present invention, a polyvinylalcohol film is provided which is readily soluble in borate containingsolutions. The film comprises a composition selected from the groupconsisting of a polyvinyl alcohol film containing a polyhydroxy compound(PHC) that reacts with borate in aqueous solution to form a borate-PHCComplex with a binding constant, K₂ being defined as equal to ##EQU1##that is greater than about 800M⁻² at 25° C.; and a polyvinyl alcoholfilm containing an acid having an acid dissociation constant, in waterat 25° C., greater than about 10⁻⁹ M, the composition being selectedsuch that 50% or more, by volume, of a 1.5 cm×1.5 cm×0.0038 cm piece ofsaid film, when agitated in a volume of 750 cc of a solution having aborate concentration of about 1.7×10⁻³ M and having a pH of about 10.7in a cylindrical container 9.5 cm in diameter using an oblong magneticstirring bar about 1 cm×5 cm at a speed sufficient to cause a vortex toextend about 20% of the way downwardly from a top surface of thesolution, substantially dissolves or disperses, as determined by visualevaluation, in 300 seconds at 37.5° C.

In accordance with another embodiment of the present invention a laundryadditive combination is provided. The laundry additive combinationincludes the laundry additive and a sealed envelope containing thatadditive. The envelope is formed of a polyvinyl alcohol film, which filmincorporates means for solubilizing the envelope sufficiently so that apiece of the film will dissolve when tested as previously set forth.

The present invention thus solves the problem of providing polyvinylalcohol films which will rapidly dissolve in solutions which containborate at levels and pHs normally encountered in laundry applications.

BEST MODE FOR CARRYING OUT THE INVENTION

When the term polyvinyl alcohol is used herein this term is meant toinclude the polyvinyl alcohol itself, derivatives thereof, and its watersoluble copolymers. The polyvinyl alcohol resins described herein aregenerally produced by the hydrolysis of polyvinyl acetate and generallyhave a degree of hydrolysis between about 70% and about 98%.

It is well known that envelopes made of polyvinyl alcohol films can beused to enclose premeasured amounts of laundry additives such asdetergents, bleaches, brighteners, builders, fabric softeners, and thelike. Such polyvinyl alcohol films are generally formed from polyvinylalcohol resins of a desired degree of hydrolysis. In practice, thepolyvinyl alcohol is dissolved in water, with heating, and one oranother conventional plasticizers, such as, for example, polyethyleneglycol having a molecular weight of 200 to 600, release agents, and ananti-blocking agent, if desired, are also dissolved in the samesolution. Thereafter, the solution is simply cast and the waterevaporated to produce a film with the desired physical properties.

The conventional polyvinyl alcohol films of the prior art have veryadequate solubility in water. However, when there is a significantborate concentration in the water and when the pH is that frequentlyencountered in washing liquors, such polyvinyl alcohol films will notdissolve sufficiently readily to deliver a laundry additive to thesolution early in the wash cycle.

An objective test, which simulates results found for top loadingautomatic washing machines, has been developed for determining when apolyvinyl alcohol film will have sufficient solubility in boratecontaining solutions so as to be readily soluble under normal laundryconditions. Acceptable solubility rate is demonstrated when at least 50%by volume of a 1.5 cm×1.5 cm×0.0038 cm sample of the film substantiallydissolves or disperses within 300 seconds, as determined by visualevaluation, in a mildly agitated aqueous solution having a borateconcentration of 1.7×10³¹ 3 M and having a pH of about 10.7 at atemperature of 37.5° C. Mild agitation is defined, for the purposes ofthe test, as agitation in a volume of 750 cc of the solution in acylindrical container 9.5 cm in diameter using an oblong magneticstirring rod about 1 cm×5 cm at a speed sufficient to cause a vortex toextend about 20% of the way downwardly from the surface of the solution.

It has been discovered that when the film is any one of threecompositions, or any mixtures of such compositions in sufficientquantities, a film results which satisfies the above-set-out test and isacceptable for laundry use.

The first composition which satisfies the test is a polyvinyl alcoholfilm produced from polyvinyl alcohol resins characterized by having anumber average molecular weight below about 50,000, more preferablybelow about 25,000, and still more preferably of about 10,000. When thisfirst composition is utilized without any of the second or thirdcompositions set out below, at least about 50% of the polyvinyl alcoholresin on which the film is based must consist of a polyvinyl alcohol ofsuch an average molecular weight. Somewhat unexpectedly, such lowmolecular weight polyvinyl alcohol resins produce films of sufficientstrength, stability in humid weather, and integrity for storage andlaundry use.

A second composition which will satisfy the above test, either by itselfor in combination with first constituent or the third constituent whichwill be set out below, or with both the first and third constituents, isa polyvinyl alcohol film which contains a polyhydroxy compound (PHC)which reacts with borate in aqueous solution to form a borate-PHCComplex with a binding constant (K₂) as defined by the equation ##EQU2##that is greater than about 800M⁻² at 25° C.; the constituentsconcentrations being in moles per liter. Particularly useful polyhydroxycompounds are levulose (fructose), mannitol, catechol, sorbitol,sorbose, pentaerythritol and meso-erythritol. In general, the higher thebinding constant, the more effective the polyhydroxy compound inproviding the desired solubility characteristics. The term "borate-PHCComplex" is generally understood by practitioners of reasonable skill inthe art to denote complexation compounds formed between a borate ionspecies and a polyhydroxy or polyol compound. This phenomenon is wellknown and amply depicted in the literature. It is somewhat surprisingthat significant quantities of the polyhydroxy compound can beincorporated into the polyvinyl alcohol without rendering envelopes madefrom the film unfit for long term storage and laundry use.

If the polyhydroxy compound is utilized by itself to solubilize thepolyvinyl alcohol film, it is preferably present in an amount of atleast about 10%, by weight, of the polyvinyl alcohol film, the effectiveamount depending on the identity of the polyhydroxy compound. On theother hand, lesser amounts of the polyhydroxy compound can be utilizedif the film includes a polyvinyl alcohol having a relatively lowermolecular weight, for example, a number average molecular weight belowabout 50,000, or if the film includes an acid as will be set out below.

A third polyvinyl alcohol film having the desired characteristics is onewhich contains an organic, inorganic or polymeric acid having an aciddissociation constant, in water at 25° C., greater than about 10⁻⁹ M andpreferably greater than about 10⁻⁶ M. Polyacrylic acids with averagemolecular weights in the range from about 3000 to about 150,000 are veryuseful acids for such purposes. Other acids are also useful, forexample, citric acid, succinic acid, tartaric acid, potassium hydrogenphthalate, sodium dihydrogen phosphate, adipic acid, cysteine, glutamicacid, benzoic acid and oxalic acid. It should be noted that when theacid is utilized by itself, it is preferred that it be in aconcentration of at least about 10%, by weight, based on the weight ofthe polyvinyl alcohol film. The amount of acid can be reduced if somepolyhydroxy compound, as set out above, is present and/or if the filmincludes polyvinyl alcohol having a number average molecular weightbelow about 50,000 and more preferably below about 25,000.

It is essential, in any case, that the polyvinyl alcohol film, inaccordance with the present invention, be capable of satisfying theobjective test of solubility in a borate containing solution and at a pHas set out above.

Thus, either a polyhydroxy compound as set out above or an acid as setout above, both limited to the characteristics set out above, serve tosolubilize the envelope in an aqueous solution having a borateconcentration of about 1.7×10⁻³ M and a pH of about 10.7 to an extentsuch that 50% or more, by volume, of a 1.5 cm×1.5 cm×0.0038 cm piece ofsaid film, when agitated in a volume of 750 cc of said solution, in acylindrical container 9.5 cm in diameter, using an oblong magneticstirring bar about 1 cm×5 cm at a speed sufficient to cause a vortex toextend about 20% of the way downwardly from the top surface of thesolution, dissolves or disperses in 300 seconds at 37.5° C.

When envelopes are made from the films, such films will generally beabout 1.5 mils thick. This provides an envelope of sufficient strengthwhich will dissolve sufficiently quickly in normal laundry use. However,film thicknesses of from about 1.0 to about 3.5 mils are practical forthe application described herein.

It should be noted that not only may detergents be enclosed in envelopesin accordance with the present invention, but also builders, bleaches,brighteners, fabric softeners, anti-soiling polymers and other laundryadditives may be so enclosed, provided they do not dissolve or otherwiseinteract deleteriously with the film material.

The invention will be better understood by reference to the followingexamples:

EXAMPLES 1-5

20.1 g of polyvinyl alcohol (number average molecular weight≃10,000, 88%hydrolyzed) was added slowly with mixing to 8.6 g of polyethylene glycol(average molecular weight≃200) and 86.4 g of distilled water. After thepolyvinyl alcohol was dispersed, the dispersion was heated forapproximately two hours at 60° C. to completely dissolve the polyvinylalcohol. The solution was cooled to 23° C., stirred slowly to remove airbubbles and cast on a glass plate using a film applicator with an 0.051cm clearance.

The resulting film was dried at room temperature for 1-2 hours, driedfurther at 37.5° C. for 2 hours and allowed to equilibrate to roomtemperature conditions (≃23° C., 50% relative humidity) before beingremoved from the glass plate for testing. This procedure yielded a film0.0038 cm thick containing approximately 66% polyvinyl alcohol, 28%polyethylene glycol and 6% water. Using the evaluation procedure as setout above, >95% of the film dissolved in 150 seconds. In this procedureborax was added as the source of borate and sodium carbonate and sodiumbicarbonate were used to maintain the pH at 10.7. Using a similarprocedure, additional films 0.0038 cm in thickness with different numberaverage molecular weight polyvinyl alcohol resins were prepared andevaluated and the results are summarized in Table I.

These examples demonstrated that a polyvinyl alcohol resin of a numberaverage molecular weight of about 50,000 or less is necessary to providea film that meets desired solubility criteria in the absence of anypolyhydroxy compound or acid. The 60% dissolved/dispersed result at 300second for 50,000 molecular weight polyvinyl alcohol is somewhat low butis quite sufficient for normal laundry use.

EXAMPLES 6-15

12.9 g of polyvinyl alcohol (average molecular weight-96,000, 88%hydrolyzed) was added slowly with mixing to 0.4 g of polyethylene glycol

                  TABLE I                                                         ______________________________________                                        Ex-                 %       % film dissolved/dispersed                        am-  Polyvinyl Alcohol                                                                            Hydro-               300                                  ple  Number Average MW                                                                            lysis   30 sec.                                                                             150 sec.                                                                             sec.                                 ______________________________________                                        1    10,000         88       95   >95    >95                                  2    26,000         88       85   >95    >95                                  3    49,000         88      <10   <10     60                                  4    78,000         88      <10   <10    <10                                  5    96,000         88      <10   <10    <10                                  ______________________________________                                         (average molecular weight≃200) and 81.6 g of distilled     water. After the polyvinyl alcohol was dispersed, the dispersion was     heated for approximately two hours at 60° C. to completely dissolve     the polyvinyl alcohol. The solution was cooled to approximately 30°     C. and a slurry of 5.1 g of fructose in 15 g of distilled water was added     with mixing. The viscous mixture was stirred for 16 hours at 23° C.     to insure complete mixing and to remove any air bubbles. It was then cast     on a glass plate using a film applicator with an 0.051 cm clearance.

The resulting film was dried at room temperature for 1-2 hours, driedfurther at 37.5° C. for 2 hours and allowed to equilibrate to roomtemperature conditions (≃23° C., 50% relative humidity) before beingremoved from the glass plate for testing. This procedure yielded a film0.0038 cm thick containing approximately 66% polyvinyl alcohol (numberaverage molecular weight≃96,000, 88% hydrolyzed), 2% polyethylene glycol(number average molecular weight≃200), 26% fructose and 6% water. Usingthe evaluation procedure as set out above, 70% of the film dissolved in300 seconds.

Using a similar procedure, additional films of a thickness ofapproximately 0.0038 cm with different polyhydroxy compounds at levelsof approximately 26% by weight were prepared and evaluated. Thepolyvinyl alcohol used in these examples was 88% hydrolyzed and had anumber average molecular weight of approximately 96,000. Table IIpresents the results of testing such films.

                  TABLE II                                                        ______________________________________                                        Ex-                                                                           am-  Polyhydroxy       % film dissolved/dispered                              ple  Compound    K.sub.2   30 sec.                                                                             150 sec.                                                                             300 sec.                              ______________________________________                                         5   (none)                <10   <10    <10                                    6   fructose    98,500    25    50     70                                     7   mannitol    88,500    80    90     95                                     8   catechol    14,200    40    50     70                                     9   pentaerythritol                                                                            1,110    40    50     70                                    10   glucose       770     <10   <10    15                                    11   arabinose     675     <10   <10    10                                    12   galactose     298     <10   <10    10                                    13   sorbitol    not known 40    60     80                                    14   sorbose     not known 30    50     75                                    15   meso-erythritol                                                                           not known <10   <10    50                                    ______________________________________                                    

These examples demonstrate that polyhydroxy compounds should have K₂values greater than about 800M⁻² to provide a film that meets desiredsolubility criteria. Furthermore, a polyvinyl alcohol film of numberaverage molecular weight greater than 50,000 has been shown to berapidly soluble due to the inclusion of these polyhydroxy compoundshaving K₂ greater than 800. Thus, polyvinyl alcohol resins of as much as200,000 number average molecular weight are expected to be renderedrapidly soluble by the correct choice of polyhydroxy compounds and itslevel in the film.

EXAMPLES 16-27

12.9 g of polyvinyl alcohol (number average molecular weight≃96,000, 88%hydrolyzed) was added slowly with mixing to 0.9 g of polyethylene glycol(average molecular weight≃200), 4.6 g of polyacrylic acid (averagemolecular weight≃5,000) and 96.6 g of deionized water. After thepolyvinyl alcohol was dispersed, the dispersion was heated forapproximately two hours at 60° C. to dissolve the polyvinyl alcohol. Thesolution was cooled at 23° C., stirred slowly to remove air bubbles andcast on a glass plate using a film applicator with an 0.051 cmclearance. The resulting film was dried at room temperature for 1-2hours, dried further at 37.5° C. for 2 hours and allowed to equilibrateat room temperature conditions (≃23° C., 50% relative humidity) beforebeing removed from the glass plate for testing. This procedure yielded afilm 0.0038 cm thick containing approximately 66% polyvinyl alcohol, 24%polyacrylic acid, 5% polyethylene glycol and 5% water. Using theevaluation procedure as set out above, >95% of the film dissolved in 150seconds.

Using a similar procedure additional films, approximately 0.0038 cmthick, containing other acids at levels of approximately 24% by weightwere prepared and evaluated. These films contained polyvinyl alcohol,88% hydrolyzed, and with a number average molecular weight ofapproximately 96,000. The results are summarized in Table III.

These examples demonstrate that acids must have K_(a) values greaterthan 10⁻⁹ M to provide a film that meets desired solubility criteria.Furthermore, a polyvinyl alcohol film of number average molecular weightgreater than 50,000 has been shown to be rendered rapidly soluble due tothe inclusion of these acidic components having K_(a) >10⁻⁹. Thus filmsbased on polyvinyl alcohol resins of as much as 200,000 number averagemolecular weight are expected to be rapidly soluble by the correctchoice of acidic compound and its level in the film.

EXAMPLE 28

Using procedures similar to those described in the previous examples, afilm combining two of the embodiments presented previously herein wasmade and evaluated. The procedure yielded a film approximately 0.0038 cmthick with a composition of approximately 81% polyvinyl alcohol (88%hydrolyzed, number average molecular weight approximately 25,000), 14%mannitol and 5% water. This film

                  TABLE III                                                       ______________________________________                                                                 % film                                               Ex-                      dissolved/dispered                                   am-                                150   300                                  ple  Acid      K.sub.a (M)   30 sec.                                                                             sec.  sec.                                 ______________________________________                                        16   polyacrylic                                                                             10.sup.-5     90    >95   >95                                  17   oxalic    6 × 10.sup.-2, 6 × 10.sup.-5                                                    <10   90    >95                                  18   glutamic  7 × 10.sup. 3, 5 × 10.sup.-5                                                    30    40    80                                   19   tartaric  1 × 10.sup.-3, 5 × 10.sup.-5                                                    40    60    85                                   20   citric    8 × 10.sup.-4, 1.8 ×                                                            60    75    90                                                  10.sup.-5, 4 × 10.sup.-6                                 21   succinic  7 × 10.sup.-5, 2 × 10.sup.-6                                                    40    40    70                                   22   benzoic   6 × 10.sup.-5                                                                         15    25    70                                   23   adipic    4 × 10.sup.-5                                                                         60    70    95                                   24   potassium 3 × 10.sup.-6                                                                         25    40    70                                        hydrogen                                                                      phthalate                                                                25   sodium    6 × 10.sup. -8                                                                        30    45    70                                        dihydrogen                                                                    phosphate                                                                26   cysteine  7 × 10.sup.-9                                                                         20    30    50                                   27   sodium    <10.sup.-9    <10   <10   <10                                       tartrate                                                                 ______________________________________                                         combines the use of a polyvinyl alcohol resin with a number average     molecular weight less than 50,000 and a polyhydroxy compound with a     binding constant with borate that is greater than 800M.sup.-2. The film     was evaluated using the procedures set forth previously and it was found     that >95% of the film by volume, dissolved or dispersed, as determined by     visual examination, in 30 seconds under the test conditions set forth     previously. This represents an improvement over either embodiment alone     (Examples 2 and 7) and although both previous examples set forth films     that met solubility criteria, this example indicates that combinations of     the embodiments yield films with still better solubility characteristics.

Better solubility characteristics can become important when the laundryadditive combination comprising a laundry additive and an envelope madefrom a film as set forth herein is used in extreme or misuse conditions.For example, it is not uncommon for the consumer to use more than therecommended amount of bleaching compositions containing sodium perboratewhen laundering a heavily soiled load or in small volumes of washingliquor. Such would result in a concentration of borate as high as3.4×10⁻³ M or even higher in the laundry liquor. Also, it is notuncommon for the consumer to launder delicate items at temperaturessignificantly less than 37.5° C. Both conditions can have the effect ofreducing the solubility rate of films that meet the criteria set forthpreviously herein.

An additional demonstration of the advantage of combining theembodiments in one film is set forth in the next examples.

EXAMPLES 29 AND 30

Using procedures similar to those described in the previous examples,two additional films were produced at a thickness of approximately0.0079 cm. The solubility rates of the two films were evaluated underconditions identical to those set forth previously herein with theexceptions that the borate concentration was maintained at 3.4×10⁻³ Mand that the temperature was maintained at 23° C. The results appear inTable IV.

Thus, although the film presented in Example 29, in which one of theembodiments of this invention is used (low molecular weight), has anacceptable solubility rate under the conditions set forth in thisexample, the solubility rate is relatively low. However, by combiningthe embodiments which teach the use of polyvinyl alcohol resins withnumber average molecular weight of about 50,000 or less, and the use ofa polyhydroxy compound which has a binding constant with borate aboveabout 800M⁻², a film is produced with a solubility rate considerablyhigher and more acceptable than that of Example 29. Thus, thecombinations of the embodiments presented herein offers significantadvantages over separate use of the individual embodiments. It can beexpected that combinations of any two of the particular embodimentspresented

                                      TABLE IV                                    __________________________________________________________________________                         Film Composition                                         % PVA 88% hydrolyzed;      % polyethylene glycol                                                                        % dissolved/dispersed               Example                                                                            Number average MW ≈ 10,000                                                            % fructose                                                                          MW ≈ 200                                                                         % H.sub.2 O                                                                       30 sec                                                                              300 sec                       __________________________________________________________________________    29   75               0    19         6   <10    60                           30   75              19     0         6   >95   >95                           __________________________________________________________________________     herein, or combinations of all three embodiments, will yield films that     readily meet solubility criteria set forth previously.

A further demonstration of the advantages of combining a low molecularpolyvinyl alcohol film and a polyhydroxy compound are set forth asfollows. Surprisingly, it has been discovered that if a low molecularweight film is combined with a typical plasticizer, e.g., polyethyleneglycol (a compound which has a binding constant with borate much lowerthan 800M⁻²), contacted with a detergent mixture of nonionic and anionicsurfactants and builders for 14-28 days, removed, and finally placed ina borate concentration of 3.4×10⁻³ M at a pH of about 10.7, at about21.1° C., such film will display poor solubility. This was unexpected,since it was believed that any relatively low molecular weight filmwould be adequately soluble even where there is a high, localized amountof perborate. Contact with the detergent, however, apparently diminishessolubility for a low molecular weight polyvinyl alcohol film, whether itis used by itself, or in combination with a plasticizer such as glycerinor polyethylene glycol.

Surprisingly, however, addition of one of the preferred polyhydroxycompounds having a binding constant with borate of more than 800M⁻² to alow molecular weight polyvinyl alcohol resulted in substantiallycomplete solubility even at the same temperature, pH and use conditions(3.4×10⁻³ M borate ion concentration), after storage in the presence ofthe previously mentioned detergent. Further, this solubility remainedconstant even after the film was aged, respectively, 14 and 28 days.This shows that if the inventive films are used in one of their mostpreferred embodiments, i.e., as a pouch to deliver detergent or otherlaundry additive, the presence of a detergent composition such as theone used in this test will not lessen the film's solubility in boratesolution to any substantial extent. These results are disclosed below inTABLE V, Examples 31-34.

                                      TABLE V                                     __________________________________________________________________________    FILM COMPOSITION                                                              (Dry Weight Basis)                                                                                                                 % DISSOLVED/                    % PVA 88% HYDROLYZED:                                                                         %      % POLYETHYLENE                                                                            %      DAYS                                                                              DISPERSED                EXAMPLE                                                                              MW 10,000       FRUCTOSE                                                                             GLYCOL      GLYCEROL                                                                             AGED                                                                              30                                                                                 300                 __________________________________________________________________________                                                              SEC.                31     80              0       0          20      0  >95  >95                 32     80              0       0          20     14  insol.                                                                              10                 33     80              0       0          20     28   10   20                 34     70              10     20          0       0  >95  >95                 35     70              10     20          0      14  >95  >95                 36     70              10     20          0      28  >95  >95                 37     80              0      20          0       0   75  >95                 38     80              0      20          0      14   15   50                 39     80              0      20          0      28  insol.                                                                              25                 __________________________________________________________________________

INDUSTRIAL APPLICABILITY

The present invention is directed to and discloses both a polyvinylalcohol film and a laundry additive-envelope combination with the filmbeing of proper solubility rate in borate containing solutions undernormal laundry conditions so as to deliver the contents of an envelopemade of the film early during a wash cycle, even when borate is present.

We claim:
 1. In a laundry additive combination, comprising:a laundryadditive; and a water soluble sealed envelope enclosing said additive,said envelope being formed of a film of plasticized polyvinyl alcohol,the improvement wherein said film additionally contains an amounteffective to render said film substantially soluble in an aqueoussolution having a borate concentration of up to about 1.7×10⁻³ M, of (a)a polyhydroxy compound, PHC, that has a binding constant, K₂, withborate, in aqueous solution at 25° C., that is greater than about800M⁻², K₂ being defined as equal to ##EQU3## wherein (Complex),(borate) and (PHC) are the molar concentrations of the respectiveconstituents; (b) an acid having an acid dissociation constant, in waterat 25° C., greater than about 10⁻⁹ M; or (c) mixtures thereof.
 2. Thelaundry additive combination, of claim 1 in which:said film issolubilized by a polyhydroxy compound selected from the group consistingof fructose, sorbitol, mannitol, sorbose, catechol, pentaerythritol andmeso-erythritol.
 3. The laundry additive combination of claim 2, whereinsaid polyhydroxy compound is mannitol.
 4. The laundry additivecombination of claim 3, wherein said film has a number average molecularweight of about 10,000.
 5. The laundry additive combination of claim 1in which:said film is solubilized by an acid selected from the groupconsisting of polyacrylic acid, citric acid, succinic acid, tartaricacid, potassium hydrogen phthalate, sodium dihydrogen phosphate, adipicacid, cysteine, glutamic acid, benzoic acid and oxalic acid.
 6. Thelaundry additive combination of claim 5, wherein said film has a numberaverage molecular weight of no more than about 50,000.
 7. The laundryadditive combination of claim 1, wherein said plasticized film issolubilized with a polyhydroxy compound as defined in (a) thereof. 8.The laundry additive combination of claim 1 wherein said plasticizedfilm is solubilized with an acid as defined in (b) thereof.